This invention is directed to a transfer tail apparatus for use with textile winders on which textile and industrial yarns are wound into packages, and particularly to an apparatus for forming a transfer tail on a yarn package support or tube, which is rotating at high speeds.
Devices and apparatus for forming transfer tails on yarn package supports, particularly on yarn package supports that are rotating at the desired yarn package winding speeds, are well known in the art. Some of these prior art devices or apparatus are represented in the Pabis patent, U.S. Pat. No. 3,276,704; the Rhein, Jr. patent, U.S. Pat. No. 3,149,795; the Nugent Patent, U.S. Pat. No. 3,224,692; the Ratti patent, U.S. Pat. No. 3,575,355; the Emery patent, U.S. Pat. No. 3,428,266; the Porter patent, U.S. Pat. No. 3,282,516; and the Bolger patent, U.S. Pat. No. 3,275,252.
The textile winders concerned with this invention usually involve a yarn package support, which may be surface-driven, and where the traversing action for even distribution of the yarn on the yarn package support may be obtained by use of a drive roll having a spiral groove in its surface to traverse the yarn as it is wound on the package, as in the case of the above-mentioned Nugent patent, U.S. Pat. No. 3,224,692. The traversing action may also be accomplished by the reciprocating motion of a yarn traverse guide through which the yarn advances to the yarn package support or tube, as in the case of the above-mentioned Pabis patent, U.S. Pat. No. 3,276,704.
The "transfer tail" is an initial wrap or turn or series of wraps or turns in the form of a single layer of a short length of helices at one end of the yarn package support or tube just outside the package portion of the tube. The purpose of the transfer tail is to facilitate the tying of the outer end of yarn from another yarn package to the transfer tail of the yarn package being processed or used in a textile mill so as to preserve the continuity of the operating process without having to shut equipment down when a yarn package becomes depleted.
The winder for which this invention, the transfer tail apparatus, is particularly adapted is the BARMAG SW4S Winder, Barmer Machinenfabrik A.G., which winds yarn onto packages at speeds in excess of 3000 meters per minute. In making transfer tails on yarn packages at these speeds any excessive slack in the winding system at the moment of the tie-up or connection of the yarn to the yarn package support or tube can cause a number of problems.
Initially, before tie-up of the yarn to the yarn package tube, the yarn is traveling toward the winder at speeds in excess of 3000 meters per minute. The yarn is being taken up by a waste aspirator or air doffer, which also serves to maintain the desired tension on the yarn. Any momentary excessive slack in tension at the moment of tie-up to the yarn package tube can cause roll wrap around the godet roll that precedes the winder. The roll wrap would thus cause a breakdown of the system. If, for whatever reason, a roll wrap should fortuitously be avoided, despite the presence of undesirable slack, and a successful tie-up should be made to the yarn package tube, slack yarn will be present in the first few layers of yarn on the yarn package tube. This can cause separated or spread filaments next to the surface of the tube, and thus cause damaged filaments.
Another problem resulting from undesirable slack is that the yarn is not pulled sufficiently tight on the traverse guide, and thus on the pickup of the yarn by the traverse guide the latter does not pick up all of the filaments at the same time, but instead picks up the remainder on the next reciprocation. This results in the filaments becoming undesirably separated, the filaments being out of phase with the other filaments and tending to cause a breakdown of the yarn end.
Still another problem resulting from excessive slack: Since the yarn layers next to the tube surface are not tensioned the same as the outer yarn layers, a potential dye take-up difference problem is created.
The separated filament problem also extends to the transfer tail when the yarn is either of low twist or is a non-TF (non-entangled filament) yarn. The filaments become separated in the transfer tail, with the possibility that the entire strand of yarn may not be tied-up to the next successive package during yarn processing. If the filaments are picked up out of phase, some of the yarn strands will be drawn more than other strands when the yarn being wound is only partially oriented. When such yarn is later processed, as by undergoing a draw texturing operation, in any dye operation the resulting different dye take-up may cause little flashes in fabric made from such yarn.
An object of the present invention is to reduce slack in the yarn to a minimum at the time of tie-up or connection of the yarn to the yarn package support or tube.
Some of the transfer tail apparatus and devices in the prior art depend on yarn tension for causing movement of the transfer tail device. Since yarn tension can vary, this will result in different movement or rotational rates in the transfer tail device which may thus cause the helices to be too closely spaced so as to make it difficult for the operator to find a yarn end and tie-up to the next yarn package. If the transfer tail is too widely spaced, the length of the tail may be too short to enable tie-up to the next yarn package.
For instance, the transfer tail device provided by Barmer Machinenfabrik A.G. on the Barmag SW4S winder comprises a light-weight arm that rotates as a result of the yarn releasing a latch and exerting a force on the arm by the tension of the yarn. The spacing between helices or turns in the transfer tail on the yarn package tube depends on the rate of rotation of the arm which in turn depends upon the tension of the yarn, bearing friction, and inertia of the arm. The latch is connected to the arm, and adjustments to account for changes in the path of the yarn to insure proper release of the latch alter the inertia of the arm. Small changes in the inertia and friction will occur and affect the rotation of the arm since the low yarn tension forces are the only forces for causing rotation of the light-weight arm.
An object of the invention, therefore, is to provide an apparatus which will enable winding of transfer tails on yarn package tubes in a controlled, repeatable manner independent of variations in yarn tension, path of the yarn, and friction changes.
Another object of the present invention is to provide a transfer tail apparatus in which yarn tension is a negligible factor in the operation of the transfer tail apparatus. Yarn tension is relied on only to hold the yarn in its proper place in the transfer tail apparatus as the yarn approaches the winder. Thus, since the transfer tail apparatus is not dependent upon yarn tension for its operation, such yarn tension otherwise tending to be variable, repeatability of the desired transfer tail is made more certain.